High throughput significance map processing for cabac in hevc

ABSTRACT

A system utilizing high throughput significance map processing for CABAC in HEVC is described. The system includes a first and second electronic device. The first electronic device encodes a block of level values, and transmits a bitstream to the second electronic device based on the encoding. The second electronic device decodes the bitstream using a high throughput significance map processing technique in order to recover video data corresponding to the block.

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/360,615 filed on Jan. 27, 2012 and entitled “LOSSLESS CODINGTECHNIQUE FOR CABAC IN HEVC”, which is a continuation-in-part of U.S.patent application Ser. No. 13/354,272 filed on Jan. 19, 2012 andentitled “HIGH THROUGHPUT BINARIZATION MODE (HTB) METHOD FOR CABAC INHEVC”, each of which is incorporated by reference herein in itsentirety.

TECHNICAL FIELD

The present disclosure relates generally to electronic devices. Morespecifically, the present disclosure relates to electronic devicesutilizing enhanced Context Adaptive Binary Arithmetic Coding (CABAC) forlossless encoding and/or decoding.

BACKGROUND

Many decoders (and encoders) receive (and encoders provide) encoded datafor blocks of an image. Typically, the image is divided into blocks andeach of the blocks is encoded in some manner, such as using a discretecosine transform (DCT), and provided to the decoder. A block may denotea rectangular region in an image and consist of pixels, for example a16×16 block is a region 16× pixels in width and 16× pixels in height.The decoder receives the encoded blocks and decodes each of the blocksin some manner, such as using an inverse discrete cosine transform.

Video coding standards, such as MPEG-4 part 10 (H.264), compress videodata for transmission over a channel with limited frequency bandwidthand/or limited storage capacity. These video coding standards includemultiple coding stages such as intra prediction, transform from spatialdomain to frequency domain, quantization, entropy coding, motionestimation, and motion compensation, in order to more effectively encodeand decode frames.

The Joint Collaborative Team on Video Coding (JCT-VC) of theInternational Telecommunication Union Telecommunication StandardizationSector (ITU-T) Study Group 16 (SG16) Working Party 3 (WP3) andInternational Organization for Standardization/InternationalElectrotechnical Commission (ISO/IEC) Joint Technical Committee1/Subcommittee 29/Working Group 11 (JTC1/SC29/WG11) has launched astandardization effort for a video coding standard called the HighEfficiency Video Coding standard (HEVC). Similar to some prior videocoding standards, HEVC is block-based coding. An example of a known HEVCencoder is shown in FIG. 1. HEVC decoders are also known.

In HEVC, Context-Adaptive Binary Arithmetic Coding (CABAC) is used tocompress Transformed and Quantized Coefficients (TQCs) without loss. TheTQCs are determined at the encoder by processing image blocks with aforward transform to generate transform coefficients that are thenquantized using an operation that maps multiple transform coefficientvalues to TQCs values. The TQCs values are then communicated to thedecoder as Coefficient Level values, or level values, and the levelvalue for each coefficient is then mapped to a transform coefficientvalue that is similar, but not necessarily identical to, the transformcoefficient value computed at the encoder. CABAC based encoding and/ordecoding technique is generally context adaptive which refers to (i)adaptively coding symbols based on the values of previous symbolsencoded and/or decoded in the past, and (ii) context, which identifiesthe set of symbols encoded and/or decoded in the past used foradaptation. The past symbols may be located in spatial and/or temporaladjacent blocks. In many cases, the context is based upon symbol valuesof neighboring blocks.

As mentioned above, CABAC may be used to compress TQCs without loss. Byway of background, TQCs may be from different block sizes according totransform sizes (e.g., 4×4, 8×8, 16×16, 32×32, 16×32). Two-dimensional(2D) TQCs may be converted into a one-dimensional (1D) array beforeentropy coding. In an example, 2D arrayed TQCs in a 4×4 block may bearranged as illustrated in Table (1).

TABLE (1) 4 0 1 0 3 2 −1  . . . −3 0 . . . . . . 0 . . . . . . . . .

When converting the 2D TQCs into a 1D array, the block may be scanned ina diagonal zig-zag fashion. Continuing with the example, the 2D arrayedTQCs illustrated in Table (1) may be converted into 1D arrayed TQCs [4,0, 3, −3, 2, 1, 0, −1, 0, . . . ] by scanning the first row and firstcolumn, first row and second column, second row and first column, thirdrow and first column, second row and second column, first row and thirdcolumn, first row and fourth column, second row and third column, thirdrow and second column, fourth row and first column and so on.

The 1D array of TQCs is represented by a sequence of Syntax Elements(SEs) in CABAC. An example of the sequence of SEs for the example 1Darray of TQCs is shown in FIG. 2. The SEs represent the followingparameters: Last position X/Y, Significance Map, and the attributesGreater than 1, Greater than 2, Sign Information, and Absolute −3. Thelast position X/Y represents the position (X/Y) of the last non-zerocoefficient in the corresponding block. Significance map represents thesignificance of each coefficient. Greater than 1 indicates whether thecoefficient amplitude is larger than one for each non-zero coefficient(i.e. with significant flag as 1). Greater than 2 indicates whether thecoefficient amplitude is larger than two for each coefficient withamplitude larger than one (i.e. with greater than 1 flag as 1).

In CABAC in HEVC, the representative SEs are coded. FIG. 3 shows theCABAC framework used for coding SEs. The CABAC coding technique includescoding symbols using stages. In the first stage, the CABAC uses a“binarizer” to map input symbols to a string of binary symbols, or“bins”. The input symbol may be a non-binary valued symbol that isbinarized or otherwise converted into a string of binary (1 or 0)symbols prior to being coded into bits. The bins can be coded into bitsusing either a “bypass encoding engine” or a “regular encoding engine”.

For the regular encoding engine in CABAC, in the second stage aprobability model is selected. The probability model is used toarithmetic encode one or more bins of the binarized input symbols. Thismodel may be selected from a list of available probability modelsdepending on the context, which is a function of recently encodedsymbols. The probability model stores the probability of a bin being “1”or “0”. In the third stage, an arithmetic encoder encodes each binaccording to the selected probability model. There are two sub-rangesfor each bin, corresponding to a “0” and a “1”. The fourth stageinvolves updating the probability model. The selected probability modelis updated based on the actual encoded bin value (e.g., if the bin valuewas a “1”, the frequency count of the “1”s is increased). The decodingtechnique for CABAC decoding reverses the process.

For the bypass encoding engine in CABAC, the second stage involvesconversion of bins to bits omitting the computationally expensivecontext estimation and probability update stages. The bypass encodingengine assumes a fixed probability distribution for the input bins. Thedecoding technique for CABAC decoding reverses the process.

The CABAC encodes the symbols conceptually using two steps. In the firststep, the CABAC performs a binarization of the input symbols to bins. Inthe second step, the CABAC performs a conversion of the bins to bitsusing either the bypass encoding engine or the regular encoding engine.The resulting encoded bit values are provided in the bitstream to adecoder.

The CABAC decodes the symbols conceptually using two steps. In the firststep, the CABAC uses either the bypass decoding engine or the regulardecoding engine to convert the input bits to bin values. In the secondstep, the CABAC performs de-binarization to recover the transmittedsymbol value for the bin values. The recovered symbol may be non-binaryin nature. The recovered symbol value is used in remaining aspects ofthe decoder.

As previously described, the encoding and/or decoding process of theCABAC includes at least two different modes of operation. In a firstmode, the probability model is updated based upon the actual coded binvalue, generally referred to as a “regular coding mode”. The regularcoding mode requires several sequential serial operations together withits associated computational complexity and significant time tocomplete. In a second mode, the probability model is not updated basedupon the actual coded bin value, generally referred to as a “bypasscoding mode”. In the second mode, there is no probability model (otherthan perhaps a fixed probability) for decoding the bins, and accordinglythere is no need to update the probability model.

When utilizing CABAC coding in HEVC, throughput performance can differdepending on different factors such as but not limited to: total numberof bins/pixels, number of bypass bins/pixels, and number of regular (orcontext) coded bins/pixels. Generally speaking, throughput for the caseof high bit-rate encoding (low Quantization Parameter (QP) value) issignificantly less than throughput in other cases. Therefore, throughputin high bit-rate cases may consume a significant amount of processingresources and/or may take a significant amount of time to encode/decode.The disclosure that follows solves this and other problems.

It is also known that CABAC can be used in a lossless coding mode tocompress a residual sample. In one example, a residual sample is a valuecorresponding to a specific location in an image. Typically, a residualsample corresponds to the difference between a value corresponding to aspecific location in an image and a prediction value corresponding tothe same, specific location in an image. Alternatively, a residualsample is a value corresponding to a specific location in an image thathas not been processed with a transformation operation, or atransformation operation that is not typically used to create TQCs. Aresidual sample can be from different block sizes according to itssample size (4×4, 8×8, 16×16, 32×32, 16×32, etc.) A 2D residual sampleblock is first converted into a 1D array before entropy coding, similarto TQC encoding. In an example, 2D arrayed residual sample in a 4×4block may be arranged as illustrated in Table (2).

TABLE (2) 4 0 1 0 3 2 −1  . . . −3 0 . . . . . . 0 . . . . . . . . .

When converting the 2D residual sample into a 1D array, the block may bescanned in a diagonal zig-zag fashion. Continuing with the example, the2D arrayed residual sample illustrated in Table (2) may be convertedinto 1D arrayed residual sample [4, 0, 3, −3, 2, 1, 0, −1, 0, . . . ] byscanning the first row and first column, first row and second column,second row and first column, third row and first column, second row andsecond column, first row and third column, first row and fourth column,second row and third column, third row and second column, fourth row andfirst column and so on.

The 1D array of the residual sample is represented by a sequence ofSyntax Elements (SEs) in CABAC. An example of a sequence of SEs for theexample 1D array of the residual sample is shown in FIG. 11. The SEsrepresent the following parameters: Last position X/Y, Significance Map,and the attributes Greater than 1, Greater than 2, Sign Information, andAbsolute −3.

In the lossless coding mode of CABAC in HEVC, the representative SEs arecoded. The CABAC framework of FIG. 3 may be used for coding the SEs. TheCABAC coding technique includes coding symbols using stages. In thefirst stage, the CABAC uses a “binarizer” to map input symbols to astring of binary symbols, or “bins”. The input symbol may be anon-binary valued symbol that is binarized or otherwise converted into astring of binary (1 or 0) symbols prior to being coded into bits. Thebins can be coded into bits using the previously described “regularencoding engine”.

For the regular encoding engine in the lossless coding mode of CABAC, inthe second stage a probability model (also known as a “context model” inthe lossless encoding mode of CABAC) is selected. The model is used toarithmetic encode one or more bins of the binarized input symbols. Thismodel may be selected from a list of available models depending on thecontext, which is a function of recently encoded symbols. The modelstores the probability of a bin being “1” or “0”. In the third stage, anarithmetic encoder encodes each bin according to the selected model.There are two sub-ranges for each bin, corresponding to a “0” and a “1”.The fourth stage involves updating the model. The selected model isupdated based on the actual encoded bin value (e.g., if the bin valuewas a “1”, the frequency count of the “1”s is increased). The decodingtechnique for CABAC decoding reverses the process.

The number of models used as described in the previous paragraph may be184. Specifically: 36 models used for Last position X/Y (18 models forLast_pos_X, 18 models for Last_pos_Y); 48 models used for SignificanceMap (4×4 block: 9 luma, 6 chroma; 8×8 block: 11 luma, 11 chroma; 16×16or 32×32 block: 7 luma, 4 chroma); and 100 models used for theattributes Greater than 1, Greater than 2, Sign Information, andAbsolute −3 (Greater_than_(—)1 flag of luma: 30; Greater_than_(—)1 flagof chroma 20, Greater_than_(—)2 flag of luma: 30; and Greater_than_(—)2flag of chroma 20).

When utilizing CABAC encoding in HEVC in the lossless coding mode,encoding/decoding is computationally complex. One reason for thecomputation complexity is the use of 184 models, as explained above. Dueto this computation complexity, encoding/decoding may consume asignificant amount of processing resources and/or may take a significantamount of time to complete. The disclosure that follows solves this andother problems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an HEVC encoder.

FIG. 2 is a table showing a sequence of syntax elements according toCABAC.

FIG. 3 is a block diagram of the CABAC framework for a sequence ofsyntax elements.

FIG. 4 is a block diagram illustrating an example of an encoder and adecoder.

FIG. 5 is a flow diagram illustrating one configuration of a method forhigh throughput binarization mode on an electronic device.

FIG. 6 is a flow diagram illustrating one configuration of encoderprocessing using high throughput binarization mode.

FIG. 7 is a flow diagram illustrating one configuration of a method forhigh throughput binarization mode on an electronic device at thedecode-side.

FIG. 8 is a flow diagram illustrating one configuration of decoderprocessing using high throughput binarization mode.

FIG. 9 illustrates a mapping table that may be used for determining aninput value in high throughput binarization mode.

FIG. 10 illustrates a plurality of binarization tables that may be usedfor adaptive binarization in high throughput binarization mode.

FIG. 11 is a table showing a sequence of syntax elements according to alossless coding mode in CABAC.

FIG. 12 is a block diagram illustrating an example of an encoder and adecoder for a lossless coding technique.

FIG. 13 is a flow diagram illustrating one configuration of a method forlossless coding on an electronic device.

FIG. 14 is a table showing a sequence of syntax elements according tothe configuration illustrated in FIG. 13.

FIG. 15 is a flow diagram illustrating one configuration of a method forlossless decoding on an electronic device at the decode-side.

FIG. 16 is a flow diagram illustrating another configuration of a methodfor lossless coding on an electronic device.

FIG. 17 is a flow diagram illustrating another configuration of a methodfor lossless coding on an electronic device at the decode-side.

FIG. 18 is a flow diagram illustrating yet another configuration of amethod for lossless coding on an electronic device.

FIG. 19 is a flow diagram illustrating yet another configuration of amethod for lossless coding on an electronic device at the decode-side.

FIGS. 20A-E are flow diagrams illustrating example configurations of anencoder or a decoder to determine whether the high throughputbinarization mode condition is met.

FIG. 21 is a flow diagram illustrating one configuration of a method fordetermining whether a high throughput mode condition is met on anelectronic device at the decode-side.

FIG. 22 is a flow diagram illustrating another configuration of a methodfor determining whether a high throughput mode condition is met on anelectronic device at the decode-side.

FIG. 23 is a block diagram illustrating an example of an encoder and adecoder.

FIG. 24 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding on an electronic device at thedecode-side.

FIG. 25 is a flow diagram illustrating another configuration of a methodfor high throughput significance map decoding on an electronic device atthe decode-side.

FIG. 26 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding with a decode-bypass featureon an electronic device at the decode-side.

FIG. 27 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding with a decode-method-switchingfeature on an electronic device at the decode-side.

DETAILED DESCRIPTION

FIG. 4 is a block diagram illustrating an example of an encoder and adecoder.

The system 400 includes an encoder 411 to generate encoded blocks to bedecoded by a decoder 412. The encoder 411 and the decoder 412 maycommunicate over a network.

The encoder 411 includes an electronic device 421 configured to encodeusing high throughput binarization mode. The electronic device 421 maycomprise a processor and memory in electronic communication with theprocessor, where the memory stores instructions being executable by theprocessor to perform the operations shown in FIGS. 5 and 6.

The decoder 412 includes an electronic device 422 configured to decodeusing the high throughput binarization mode. The electronic device 422may comprise a processor and memory in electronic communication with theprocessor, where the memory stores instructions being executable toperform the operations shown in FIGS. 7 and 8.

FIG. 5 is a flow diagram illustrating one configuration of a method forhigh throughput binarization mode on an electronic device.

In block 511, the electronic device 421 obtains a block of transformedand quantized coefficients (TQCs). In diamond 512, the electronic device421 determines whether a high throughput binarization mode condition ismet. If the condition is not met in diamond 512, then in block 513 theelectronic device 421 codes the block by selectively using a regularcoding mode and a bypass coding mode (according to conventional CABACselection schemes).

If the condition is met in diamond 512, then in block 514 the electronicdevice 421 uses high throughput binarization mode and bypass coding modeto code the block. The electronic device 421 transmits the generatedbitstream over a network and/or stores the generated bitstream in amemory device in block 515.

HTB mode uses bypass coding mode for coding the level values. Incontrast to regular encoding mode, bypass coding omits thecomputationally expensive context estimation and probability updatestages because bypass coding mode assumes a fixed probabilitydistribution for the input bins.

In addition to using bypass coding mode for coding, by way of contrastto conventional CABAC, HTB mode uses simplified signing structure forcoding. For example, conventional CABAC requires four sub-parts forcoding, including Greater_than_(—)1, Greater_than_(—)2, Signinformation, and Absolute −3.

FIG. 6 is a flow diagram illustrating one configuration of encoderprocessing using high throughput binarization mode.

The blocks 612-615 illustrate operations performed in block 514 in moredetail. In block 612, the electronic device 421 generates sign and levelinformation for any non-zero values from the block of TQCs by applyingan absolute value minus one function to each non-zero value and checkingthe sign of each non-zero value. For ease of explanation, consider thevalues for the 1D arrayed TQC from the background section of the presentapplication [4, 0, 3, −3, 2, 1, 0, −1, 0, . . . ]. Applying the absolutevalue minus one function to each non-zero value and checking the sign ofeach non-zero value generates six combinations of sign and levelinformation as follows: +3, +2, −2, +1, +0, and −0.

In block 613, the electronic device 421 maps an input value to eachgenerated combination of sign and level information using a mappingtable. An example mapping table is shown in FIG. 9. FIG. 9 also shows anequation for determining an input value according to blocks 612 and 613.

In block 614, the electronic device 421 performs adaptive binarizationof the input values using a plurality of binarization tables, e.g. theVLC tables of Context Adaptive Variable Length Coding (CAVLC). Anexample of the VLC tables of CAVLC is shown in FIG. 10. FIG. 10 alsoshows an equation for updating the binarization tables based on previousinput information.

In an example, block 614 may include initially using values from thecolumn VLC-Table-0 (FIG. 10) to binarize at least the first input value.The VLC table number may be monotonically increased when a previousvalue is larger than the given threshold values, e.g. 3, 5, 13, 27.Accordingly, subsequent adaptive binarization after the firstmonotomical increase may use values from the column VLC-Table-1,subsequent adaptive binarization after the second monotomical increasemay use values from the column VLC-Table-2, etc.

In block 615, the electronic device 421 encodes the resultant values ofthe adaptive binarization using the CABAC bypass coding mode.

High Throughput Binarization Mode Condition

In an example, if a characteristic corresponding to a block of imagedata is greater than a preset threshold, then the high throughputbinarization mode condition is met, e.g. the electronic device 421 mayset a high throughput binarization mode indicator, e.g. an HTB modeflag, to a value of 1 (which of course may include changing a defaultvalue of the HTB mode flag or leaving the HTB mode flag at a defaultvalue depending on design preference).

In an example, the electronic device 421 determines whether a bit ratefor a coding is greater than a preset threshold. If the bit rate isgreater than the preset threshold, then the high throughput binarizationmode condition is met. In an example, the preset bit rate thresholdcorresponds to QP 16; however, a preset threshold corresponding todifferent QP values may be used.

In an example, the determination (by the electronic device 421 or theelectronic device 422) of whether the high throughput binarization modecondition is met is based on whether the transform unit level (forexample but not limited to the level values generated by a transformunit) of a corresponding block of image data is greater than a presetthreshold.

In an example, the high throughput binarization mode condition can bemet when the number of level values of a corresponding block of imagedata and with magnitude greater than zero is greater than a presetthreshold, e.g. 8. In another example, the high throughput binarizationmode condition is met when the number of level values of a correspondingblock of image data and with magnitude greater than a first presetthreshold is greater than a second preset threshold. In yet an example,the high throughput binarization mode condition is met when a levelvalue of a corresponding block of image data is greater than a presetthreshold.

The FIGS. 20A-E show some examples of configurations that may be usedfor an encoder or decoder in example systems operating according to atleast some of the principles described in the immediately preceding twoparagraphs. FIG. 20A illustrates processes 1611-1616, as shown. FIG. 20Billustrates processes 1711-1716, as shown. FIG. 20C illustratesprocesses 1801-1805 and 1814-1820. FIG. 20D illustrates processes1901-1905 and 1914-1920. In FIG. 20E, the processes of FIG. 20C areperformed up until process 1816, as shown. If the counter is greaterthan the threshold in process 1816, then the configuration continues asshown in FIG. 20E.

In an example, the determination (by the electronic device 421 or theelectronic device 422) of whether the high throughput binarization modecondition is met is based on whether the slice level of a correspondingblock of image data is greater than a preset threshold.

High Throughput Binarization Mode Indicator

In an example, the electronic device 421 is configured to set a highthroughput binarization indicator, e.g. an HTB mode flag, in a header,e.g. the slice header. The high throughput binarization indicator may beused to determine whether or not the process shown in FIG. 5 is executedfor block(s) corresponding to the slice header.

In an example, setting the HTB mode flag to “1” causes the electronicdevice 421 to perform the process shown in the flowchart of FIG. 5 forblock(s) corresponding to the slice header in response to observing theHTB mode flag value of “1”. Setting the HTB mode flag to “0” causes theelectronic device 421 to encode block(s) corresponding to the sliceheader according to a conventional CABAC technique in response toobserving the HTB mode flag value of “0”.

The HTB mode flag value may also be observed by the electronic device422 for decoding. In an example, the electronic device 422 decodesblock(s) corresponding to a slice header having the HTB mode flag valueof “1” according to the process shown in the flowchart of FIG. 7 forblock(s) corresponding to the slice header in response to observing theHTB mode flag value of “1”. The electronic device 422 decodes block(s)corresponding to a slice header having the HTB mode flag value of “0”according to a conventional CABAC technique in response to observing theHTB mode flag value of “0”.

FIG. 7 is a flow diagram illustrating one configuration of a method forhigh throughput binarization mode on an electronic device at thedecode-side.

In block 710, the electronic device 422 obtains a bitstream. In block711, the electronic device 422 recovers a binary symbol from theobtained bitstream.

In diamond 712, the electronic device 422 determines whether a highthroughput binarization mode condition is met. In an example, thedetermination may include checking a header, such as a slice header,corresponding to the received bitstream. Checking the header may furthercomprise checking a slice header corresponding to the obtained bitstream for a value of a high throughput binarization mode indicator. Ifthe condition is not met in diamond 712, then in block 713 theelectronic device 422 decodes the binary symbol by selectively usingregular decoding mode and bypass coding mode.

If the condition is met in diamond 712, then in block 714 the electronicdevice 421 uses high throughput binarization mode and bypass decodingmode to decode the binary symbol. The electronic device 422 may store anobtained block of TQCs in a memory device and/or may recover video datain block 715.

FIG. 8 is a flow diagram illustrating one configuration of decoderprocessing using high throughput binarization mode.

The blocks 812-815 illustrate operations performed in block 714 in moredetail. In block 812, the electronic device 422 bypass decodes theencoded binary symbol. In block 813, the electronic device 422de-binarizes a result of the bypass decoding. In block 814, theelectronic device 422 maps recovered input values from thede-binarization to sign and level information using a mapping table. Inblock 815, the electronic device 422 decodes a block of transformed andquantized coefficients (TQCs) using the sign and level information.

In an example, an electronic device including a processor and a memoryin electronic communication with the processor is provided. Stored inthe memory are instructions executable by the processor to performoperations.

In an example, an operation may include obtaining a block of transformedand quantized coefficients (TQCs). Another operation may includedetermining whether a high throughput binarization mode condition ismet. Another operation may include generating a first bitstream usingthe high throughput binarization mode in response to determining thatthe high throughput binarization mode condition is met. Anotheroperation may include generating a second bitstream in response todetermining that the high throughput binarization mode condition is notmet. Another operation may include transmitting the generated first orsecond bitstream to a decoder.

In an example, the generation of the first bitstream using the highthroughput binarization mode may include additional operations. Oneoperation may include generating sign and level information for anynon-zero values from the block by applying an absolute value minus onefunction to each non-zero value and checking the sign of each non-zerovalue. Another operation may include mapping an input value to eachgenerated combination of sign and level information using a mappingtable. Another operation may include performing adaptive binarization ofthe mapped input values using a plurality of binarization tables.Another operation may include encoding a result of the adaptivebinarization.

In an example, the plurality of binarization tables include VLC tablesof CAVLC. Encoding the result of the adaptive binarization may furtherinclude the operation of utilizing a CABAC bypassing coding mode.

In an example, the adaptive binarization of the mapped input valuesusing a plurality of binarization tables may include additionaloperations. One operation may include determining whether one of themapped input values is greater than a preset threshold. Anotheroperation may include performing a table update responsive todetermining that said mapped input value is greater than the presetthreshold.

In an example, the generation of the first bitstream may includeadditional operations. One operation may include coding the block byselectively utilizing a regular coding mode and a bypass coding modeaccording to CABAC. Another operation may include generating the firstbitstream utilizing only the bypass coding mode.

In an example, the determination of whether the high throughputbinarization mode condition is met is based on whether a characteristiccorresponding to a block of image data is greater than a presetthreshold.

In an example, the determination of whether the high throughputbinarization mode condition is met is based on whether the slice levelof a corresponding block of image data is greater than a presetthreshold.

In an example, the determination of whether the high throughputbinarization mode condition is met is based on whether the transformunit level of a corresponding block of image data is greater than apreset threshold.

Lossless Coding Technique for CABAC in HEVC

FIG. 12 is a block diagram illustrating an example of an encoder and adecoder for a lossless coding technique.

The system 1400 includes an encoder 1411 to generate encoded blocks tobe decoded by a decoder 1412. The encoder 1411 and the decoder 1412 maycommunicate over a network.

The encoder 1411 includes an electronic device 1421 configured to encodeusing a lossless coding technique for CABAC in HEVC. The electronicdevice 1421 may comprise a processor and memory in electroniccommunication with the processor, where the memory stores instructionsbeing executable by the processor to perform the operations shown inFIGS. 13, 16, and 18.

The decoder 1412 includes an electronic device 1422 configured to decodeusing a lossless coding technique for CABAC in HEVC. The electronicdevice 1422 may comprise a processor and memory in electroniccommunication with the processor, where the memory stores instructionsbeing executable to perform the operations shown in FIGS. 15, 17, and19.

FIG. 13 is a flow diagram illustrating one configuration of a method forlossless coding on an electronic device.

In block 911, the electronic device 1421 obtains a block representing aresidual sample. In one example, zig-zag scanning direction may beredefined to fit the direction of intra prediction that is used toremove the spatial redundancies between neighboring pixels. There areseveral intra prediction modes available in lossless intra coding mode.In one example, in vertical intra prediction mode, upper pixels becomethe prediction value of the current pixel value and the differencebetween the current value and the prediction value (upper pixel value invertical mode) become the residual sample value. Context model selectionmay also depend on the direction of intra prediction and thecorresponding block size.

In block 912, the electronic device 1421 generates a significance map tobe used in a sequence of syntax elements. In block 913, the electronicdevice 1421 populates a significance map field that corresponds to thelast scanning position of the block with a value corresponding to thelevel of the last position of the block.

In block 914, the electronic device 1421 generates a sequence of syntaxelements including the significance map having said value. Generatingthe sequence of syntax elements excludes the last position coding stepof conventional CABAC lossless coding mode.

FIG. 14 is a table showing a sequence of syntax elements according tothe configuration illustrated in FIG. 13.

Several differences can be observed by way of contrast of the sequenceof syntax elements shown in FIG. 14 as compared to the sequence ofsyntax elements shown in FIG. 11. The sequence of syntax elements shownin FIG. 11 includes a Last_position_X field and a Last_position_Y fieldbecause the conventional CABAC lossless coding mode includes a lastposition coding step. In contrast, the sequence of syntax elements shownin FIG. 14 does not include a Last_position_X field and aLast_position_Y field because the configuration of FIG. 14 omits thelast position coding step.

While both of the sequence of syntax elements include significance maps,there are differences between the significance maps. In the significancemap of the sequence of syntax elements of FIG. 11, a significance mapfield is unpopulated to correspond with the field ofLast_position_X/Last_position_Y that is populated. In contrast, in FIG.14 a significance map field that corresponds to the last scanningposition of the block is populated with a value, i.e. “0” for theexample block, corresponding to the level of the last position of theblock.

FIG. 15 is a flow diagram illustrating one configuration of a method forlossless decoding on an electronic device at the decode-side.

In block 1011, the electronic device 1422 recovers, from a bitstream, asequence of syntax elements having a significance map populated with avalue corresponding to a last scanning position of a block. In block1012, the electronic device 1422 decodes the levels of the block usingthe significance map and using said value of the significance map. Inblock 1013, the electronic device 1422 stores an obtained blockcorresponding to a residual value in a memory device and/or recoversvideo data.

FIG. 16 is a flow diagram illustrating another configuration of a methodfor lossless coding on an electronic device.

In block 1111, the electronic device 1421 obtains a sequence of syntaxelements representing level information for a block of a residualsample. In block 1112, the electronic device 1421 performs adaptivebinarization on values of the Absolute −3 portion of the sequence ofsyntax elements using a plurality of binarization tables, e.g. the VLCtables of CAVLC (FIG. 10), wherein the values of the Absolute −3 portionof the sequence of syntax elements are used as input values for theplurality of binarization tables. An equation for updating thebinarization tables based on previous input information is shown below:

-   -   if (‘abs[coefficient(i)]−3’>(Table[vlc])) vlc ++;    -   where Table [vlc]={3, 5, 13, 27};    -   ‘i’ represents scanning position and ‘vlc’ represents the        current vlc table number    -   *vlc is first set to zero (or one for intra slice) because there        is no available previous ‘Absolute −3’ vlc Table updated is        stopped when vlc is equal to 4

In an example, block 1111 may include initially using values from thecolumn VLC-Table-0 (FIG. 10) for inter slice and the column VLC-Table-1for intra slice to binarize at least the first input value. The VLCtable number may be monotomically increased when a previous value islarger than the given threshold values, e.g. 3, 5, 13, 27. Accordingly,subsequent adaptive binarization after the first monotomical increasemay use values from the column VLC-Table-1, subsequent adaptivebinarization after the second monotomical increase may use values fromthe column VLC-Table-2, etc.

In block 1113, the electronic device 1421 encodes the resultant valuesof the adaptive binarization using CABAC bypass coding mode.

FIG. 17 is a flow diagram illustrating another configuration of a methodfor lossless coding on an electronic device at the decode-side.

In block 1211, the electronic device 1422 recovers a binary symbol froma bitstream. In block 1212, the electronic device 1422 bypass decodesthe binary symbol. In block 1213, the electronic device 1422 adaptivelyde-binarizes a result of the bypass decoding. In block 1214, theelectronic device 1422 recovers a block representing residualinformation using a result of the adaptive de-binarization.

FIG. 18 is a flow diagram illustrating yet another configuration of amethod for lossless coding on an electronic device.

In block 1311, the electronic device 1421 accesses only a subset of thecontext models of CABAC. The number of context models of CABAC may be184. In order to generate the subset, these context models may befiltered based on associated characteristics of the context models, e.g.based on relationship to frequency component, based on which contextmodels are associated with the last position coding step of CABAC, orthe like, or any combination thereof. The filtering may be performed bythe electronic device 1421 in one example, but in other examples thesubset may be provided to the electronic device 1421 so that theelectronic device 1421 may access the provided subset for losslesscoding mode.

In one example, all the CABAC context models related to frequencycomponent may be eliminated to obtain the subset. Such a subset includes26 context models, i.e. two context models (one is for luma and theother is for chroma) used for generating the significance map, and 6context models are used for Greater_than_(—)1 flag of luma,Greater_than_(—)1 flag of chroma, Greater_than_(—)2 flag of luma, andGreater_than_(—)2 flag of chroma, respectively. Therefore, total 24context models are used for Greater_than_(—)1 and Greather_than_(—)2.

As shown In Table (3), 6 context models may depend on the sub-block typeand the number of LargerT1 in the previous sub block. Here LargerT1indicates coefficients larger than 1. For sub-blocks, different blocksizes according to its sample size (4×4, 8×8, 16×16, 32×32, 16×32, etc.)is further divided into sub-blocks and In the level coding includingGreater_than_(—)1 flag and Greater_than_(—)2 flag. Here, sub-block 0indicates the last coded sub-block. In one example, if the current blocksize is 4×4, we have one sub-block which is sub-block 0. If thecorresponding block size is 8×8, then we have 4 sub-blocks and the lastscanned (or coded) sub-block is considered to be sub-block 0. Note thatsub-block scanning method may be various.

TABLE (3) 6 context models based on sub-block type and LargerT1 0 Subblock 0 0 LargerT1 in previous subset 1 1-3 LargerT1 in previous subset2 >3 LargerT1 in previous subset 3 Other sub 0 LargerT1 in previoussubset 4 blocks 1-3 LargerT1 in previous subset 5 >3 LargerT1 inprevious subset

In block 1312, the electronic device 1421 uses the subset of the contextmodels to code the significance map.

FIG. 19 is a flow diagram illustrating yet another configuration of amethod for lossless coding on an electronic device at the decode-side.

In block 1511, the electronic device 1422 accesses only a subset of thecontext models of CABAC. In block 1512, the electronic device 1422recovers a binary symbol from a bitstream using the subset of contextmodels. In block 1513, the electronic device 1422 recovers video datausing a result of the decoding.

In the foregoing, configurations that may be implemented by theelectronic device 1421 are illustrated in FIGS. 13, 16, and 18.Configuring an encoder with all of these configurations improves codingperformance compared to known CABAC lossless coding mode. Nevertheless,configuring an encoder with less than all of these configurations in anycombination, e.g. one of these configurations or any two of theseconfigurations, is also possible and practical, and also improves codingperformance compared to known CABAC lossless coding mode.

In the foregoing, configurations that may be implemented by theelectronic device 1422 are illustrated in FIGS. 14, 17, and 19.Configuring a decoder with all of these configurations improves codingperformance compared to known CABAC lossless coding mode. Nevertheless,configuring a decoder with less than all of these configurations in anycombination, e.g. one of these configurations or any two of theseconfigurations, is also possible and practical, and also improves codingperformance compared to known CABAC lossless coding mode.

In an example, an electronic device including a processor and a memoryin electronic communication with the processor is provided. Stored inthe memory are instructions executable by the processor to performoperations.

In an example, an operation may include obtaining a block representing aresidual sample for lossless encoding. Another operation may includegenerating a significance map, wherein the generating includespopulating a significance map field that corresponds to the lastscanning position of the block with a value corresponding to a level ofthe last scanning position of the block. Another operation may includegenerating a sequence of syntax elements including the significance maphaving the value. Another operation may include transmitting a bitstreamrepresenting the generated sequence of syntax elements to a decoder.

In an example, the sequence of syntax elements is generated withoutperforming the last position coding step of Context Adaptive BinaryArithmetic Coding (CABAC).

In an example, another operation may include performing perform adaptivebinarization using a plurality of binarization tables, wherein values ofan Absolute −3 portion of the sequence of syntax elements are used asinput values for the plurality of binarization tables. Another operationmay include encoding a result of the adaptive binarization. Theplurality of binarization tables may be VLC tables of CAVLC.

In an example, encoding the result of the adaptive binarization mayinclude additional operations. An additional operation may includeutilizing a CABAC bypassing coding mode.

In an example, the adaptive binarization of the input values using theplurality of binarization tables may include additional operations. Anadditional operation may include determining whether one of the inputvalues is greater than a preset threshold. An additional operation mayinclude performing a table update responsive to determining that saidinput value is greater than the preset threshold.

In an example, another operation may include accessing only a subset ofthe context models of CABAC. Another operation may include using thesubset of the context models to code the significance map. The subsetmay comprise the context models of CABAC that do not represent frequencycomponent(s).

In an example, an electronic device including a processor and a memoryin electronic communication with the processor is provided. Stored inthe memory are instructions executable by the processor to performoperations.

In an example, an operation may include obtaining a block representing aresidual sample for lossless encoding. Another operation may includegenerating a sequence of syntax elements to represent the block. Anotheroperation may include performing adaptive binarization using a pluralityof binarization tables, wherein values of an Absolute −3 portion of thesequence of syntax elements are used as input values for the pluralityof binarization tables. Another operation may include encoding a resultof the adaptive binarization. Another operation may include transmittingthe encoding to a decoder.

In an example, the plurality of binarization tables are VLC tables ofCAVLC.

In an example, encoding the result of the adaptive binarization mayinclude additional operations. An additional operation may includeutilizing a Context Adaptive Binary Arithmetic Coding (CABAC) bypassingcoding mode.

In an example, the adaptive binarization of the input values using theplurality of binarization tables may include additional operations. Anadditional operation may include determining whether one of the inputvalues is greater than a preset threshold. An additional operation mayinclude performing a table update responsive to determining that saidinput value is greater than the preset threshold.

In an example, another operation may include generating a significancemap, wherein the generating includes populating a significance map fieldthat corresponds to the last scanning position of the block with a valuecorresponding to a level of the last scanning position of the block.Another operation may include generating the sequence of syntax elementsusing the generated significance map.

In an example, the sequence of syntax elements is generated withoutperforming the last position coding step of CABAC.

In one example, a method is provided. The method may be performed usinga decoder. One operation of the method may include filtering the contextmodels of Context Adaptive Binary Arithmetic Coding (CABAC) based onrelationship to frequency component. Another operation of the method mayinclude obtaining a bitstream. Another operation of the method mayinclude recovering a binary symbol from the bitstream. Another operationof the method may include decoding the binary symbol using the filteredcontext models. Another operation of the method may include recoveringvideo data using a result of the decoding.

In an example, another operation may include recovering, from thebitstream, a sequence of syntax elements having a significance mappopulated with a value corresponding to a last scanning position of ablock representing a residual sample. Another operation may includedecoding the levels of the block using the significance map and usingsaid value of the significance map.

In an example, the decoding of the levels of the block may be performedwithout performing the last position decoding step of CABAC.

In an example, another operation may include bypass decoding therecovered binary symbol. Another operation may include adaptivelyde-binarizing a result of the bypass decoding. Another operation mayinclude recovering a block representing residual information using aresult of the de-binarization.

In an example, another operation may include using a plurality of VLCtables of CAVLC for the adaptive de-binarization.

In an example, the bypass decoding may include utilizing a CABAC bypassdecoding mode.

FIG. 21 is a flow diagram illustrating one configuration of a method fordetermining whether a high throughput mode condition is met on anelectronic device at the decode-side.

In block 2611, the electronic device 422 obtains a bitstream. In block2612, the electronic device 422 obtains a block of level values. In anexample, the block comprises a block of TQCs.

In block 2613, the electronic device 422 determines the number of levelvalues that are not equal to zero. In diamond 2614, the electronicdevice 422 determines whether the number is greater than a presetthreshold. In an example, the preset threshold may be 8, which is halfof the number of values of a 4×4 block. In examples with a block sizehaving N level values, the threshold may correspond to 50% of N. In anexample, the electronic device 422 receives signaling from theelectronic device 421. The signaling transmitted by the electronicdevice 421 may specify the preset threshold or include information thatmay be used by the electronic device 421 for determining the presetthreshold.

If the number is not greater than the preset threshold in diamond 2614,then in block 2615 the electronic device 422 decodes level values notequal to zero with a first binarization method. If the number is greaterthan the preset threshold in diamond 2614, then in block 2616 theelectronic device 422 decodes level values not equal to zero with asecond binarization method that is different than the first binarizationmethod. In an example, the second binarization method may comprise ahigh throughput debinarization mode, such as the previously describedHTB mode. In an example, the first binarization method may comprisebinarization of conventional CABAC.

FIG. 22 is a flow diagram illustrating another configuration of a methodfor determining whether a high throughput mode condition is met on anelectronic device at the decode-side.

In block 2711, the electronic device 422 obtains a bitstream. In block2712, the electronic device 422 obtains a block of level values. In anexample, the block comprises a block of TQCs.

In block 2713, the electronic device 422 determines the number of levelvalues with an absolute value greater than a first preset threshold. Inan example, the first preset threshold may be either 1 or 2, althoughother first preset thresholds may be used in other examples. In diamond2714, the electronic device 422 determines whether the number is greaterthan a second preset threshold. In an example, the second presetthreshold may be 8, which is half of the number of values of a 4×4block. In examples with a block size having N level values, the secondpreset threshold may correspond to 50% of N.

In an example, the electronic device 422 receives signaling from theelectronic device 421. The signaling transmitted by the electronicdevice 421 may specify the first preset threshold and/or the secondpresent threshold, or include information that may be used by theelectronic device 421 for determining the first preset threshold and/orthe second present threshold.

If the number is not greater than the second preset threshold in diamond2714, then in block 2715 the electronic device 422 decodes level valuesnot equal to zero with a first binarization method. If the number isgreater than the preset threshold in diamond 2714, then in block 2716the electronic device 422 decodes level values not equal to zero with asecond binarization method that is different than the first binarizationmethod. In an example, the second binarization method may comprise ahigh throughput debinarization mode, such the previously described HTBmode. In an example, the first binarization method may comprisebinarization of known CABAC decoding.

FIG. 23 is a block diagram illustrating an example of an encoder and adecoder.

The system 2400 includes an encoder 2411 to generate encoded blocks tobe decoded by a decoder 2412. The encoder 2411 and the decoder 2412 maycommunicate over a network.

The decoder 2412 includes an electronic device 2422 configured to decodeusing the high throughput significance map processing. The electronicdevice 2422 may comprise a processor and memory in electroniccommunication with the processor, where the memory stores instructionsbeing executable to perform the operations shown in FIGS. 24-27.

The encoder 2411 includes an electronic device 2421, which may comprisea processor and memory in electronic communication with the processor,where the memory stores instructions being executable by the processorto perform operations that will be understood by one of ordinary skillin the art from the description of the configurations shown in FIGS.24-27 and the corresponding description thereof.

FIG. 24 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding on an electronic device at thedecode-side.

In block 2801, the electronic device 2422 obtains a bitstream. In block2802, the electronic device 2422 obtains a block of level values. In anexample, the block comprises a block of TQCs. In block 2803, theelectronic device 2422 obtains a level value of the block, e.g. thefirst level value of the block or a next level value of the block.

In diamond 2804, the electronic device 2422 determines whether theobtained level value is the last level value of the block. If theobtained level value is not the last level value in diamond 2804, thenthe electronic device 2422 proceeds to diamond 2814. If the obtainedlevel value is the last level value in diamond 2804, then in block 2805the electronic device 2422 decodes magnitudes of the level values (whichmay include determining both sign information and absolute magnitude foreach level value).

Referring again to diamond 2814—the electronic device 2422 determineswhether the obtained level value is not zero using a first decodingmethod. If the obtained level value is not zero in diamond 2814, theelectronic device 2422 proceeds to block 2815; otherwise, the electronicdevice 2422 returns to block 2803. In block 2815, the electronic device2422 increments a counter.

In diamond 2816, the electronic device 2422 determines whether a currentcount of the counter is greater than a preset threshold. In an example,the preset threshold may comprise the preset threshold described withreference to FIG. 21. If the current count of the counter is greaterthan the preset threshold in diamond 2816, the electronic device 2422proceeds to block 2817; otherwise, the electronic device 2422 returns toblock 2803.

In block 2817, the electronic device 2422 obtains the next level valueof the block. In diamond 2818, the electronic device 2422 determineswhether the obtained level value is the last level value of the block.If the obtained level value is not the last level value in diamond 2818,then the electronic device 2422 proceeds to block 2819; otherwise, inblock 2820 the electronic device 2422 decodes magnitudes of the levelvalues.

In block 2819, the electronic device 2422 determines whether theobtained level value is not zero using a second decoding method that isdifferent than the first decoding method. In an example, the seconddecoding method comprises a high throughput decoding method, a bypassdecoding method, or the like. In an example, the first decoding methodis comprises the regular decoding mode of CABAC.

According to the above, a significance map may be decodedelement-by-element, e.g. significance map field-by-significance mapfield. When the preset threshold is reached, the electronic device 2422may change the decoding of the remaining significance map portion. Ahigh throughput or bypass significance map decoding mode may be used forthe remaining significance map portion. Therefore, decoding performancemay be improved over conventional CABAC significance map decoding.

FIG. 25 is a flow diagram illustrating another configuration of a methodfor high throughput significance map decoding on an electronic device atthe decode-side.

In the method shown in FIG. 25, processes 2901-2905 may be performed asshown, similar to processes 2801-2805 (FIG. 24). In diamond 2914, theelectronic device 2422 determines whether the absolute value of theobtained level value is greater than a first threshold using a firstdecoding method. In an example, the first threshold may be either 1 or2, although other first thresholds may be used in other examples. If theabsolute value of the obtained level value is greater than the firstthreshold in diamond 2914, the electronic device 2422 proceeds to block2915; otherwise, the electronic device 2422 returns to block 2903. Inblock 2915, the electronic device 2422 increments a counter.

In diamond 2916, the electronic device 2422 determines whether a currentcount of the counter is greater than a second preset threshold. In anexample, the second preset threshold may be 8, which is half of thenumber of values of a 4×4 block. In examples with a block size having Nlevel values, the second preset threshold may correspond to 50% of N. Ifthe current count of the counter is greater than the second threshold indiamond 2916, the electronic device 2422 proceeds to block 2917;otherwise, the electronic device 2422 returns to block 2903.

In block 2917, the electronic device 2422 obtains the next level valueof the block. In diamond 2918, the electronic device 2422 determineswhether the obtained level value is the last level value of the block.If the obtained level value is not the last level value in diamond 2918,then the electronic device 2422 proceeds to block 2919; otherwise, inblock 2920 the electronic device 2422 decodes magnitudes of the levelvalues.

In block 2919, the electronic device 2422 determines whether theabsolute value of the obtained level value is greater than the firstthreshold using a second decoding method that is different than thefirst decoding method. In an example, the second decoding methodcomprises a high throughput decoding method, a bypass decoding method,or the like. In an example, the first decoding method is comprises theregular decoding mode of CABAC.

According to the above, a significance map may be decodedelement-by-element, e.g. significance map field-by-significance mapfield. When the preset threshold is reached, the electronic device 2422may change the decoding of the remaining significance map portion. Ahigh throughput or bypass significance map decoding mode may be used forthe remaining significance map portion. Therefore, decoding performancemay be improved over conventional CABAC significance map decoding.

FIG. 26 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding with a decode-bypass featureon an electronic device at the decode-side.

In the method shown in FIG. 26, processes 3001-3004 and 3014-3016 may beperformed as shown, similar to processes 2801-2804 and 2814-2816 (FIG.24). In block 3005, the electronic device 2422 recovers magnitudes ofthe level values using a third decoding method, e.g. a binarizationmethod. In block 3020, the electronic device 2422 recovers magnitudes ofa first portion of the level values using the third decoding method, andrecovers magnitudes of a second portion of the level values using afourth decoding method, e.g. a different binarization method.

In an example, the first portion of the level values comprises the levelvalues processed with the first decoding method. The second portion ofthe level values comprises the level values not processed with the firstdecoding method.

It should be apparent that other configurations of a method for highthroughput significance map decoding with a decode-bypass feature on anelectronic device at the decode-side similar to the configuration shownin FIG. 26 may be possible and practical. For example, in anotherconfiguration, the electronic device 2422 determines if the absolutevalue of the obtained level value is greater than a first presetthreshold using a first decoding method, similar to diamond 2914 (FIG.25). Also, the electronic device 2422 determines whether the counter isgreater than the second preset threshold, similar to diamond 2916 (FIG.25).

According to the above, a significance map may be decodedelement-by-element, e.g. significance map field-by-significance mapfield. When the preset threshold is reached, the electronic device 2422may stop decoding the significance map (the remaining elements of thesignificance map are not decoded). Thereafter, the level values thatcorrespond to the decoded elements are processed using a binarizationmethod (e.g. a binarization method that can send the value zero), whilethe remaining elements are processed using a different binarizationmethod (e.g. a binarization method that cannot send the value zero).Therefore, decoding performance may be improved over conventional CABACsignificance map decoding.

FIG. 27 is a flow diagram illustrating a configuration of a method forhigh throughput significance map decoding with a decode-method-switchingfeature on an electronic device at the decode-side.

In the method shown in FIG. 27, processes 3801-3804 and 3814-3819 may beperformed as shown, similar to processes 2801-2804 and 2814-2819 (FIG.24). In block 3805, the electronic device 2422 recovers magnitudes ofthe level values using the third decoding method (the third decodingmethod of FIG. 26). In block 3820, the electronic device 2422 recoversmagnitudes of a first portion of the level values using the thirddecoding method, and recovers magnitudes of a second portion of thelevel values using the fourth decoding method (the fourth decodingmethod of FIG. 26). In an example, the first portion of the level valuescomprises the level values obtained in block 3803, while the secondportion of the level values comprises the level values obtained in block3817.

It should be apparent that other configurations of a method for highthroughput significance map decoding with a decode-bypass feature on anelectronic device at the decode-side similar to the configuration shownin FIG. 27 may be possible and practical. For example, in anotherconfiguration, the electronic device 2422 determines if the absolutevalue of the obtained level value is greater than a first presetthreshold using a first decoding method, similar to diamond 2914 (FIG.25). Also, the electronic device 2422 determines whether the counter isgreater than the second preset threshold, similar to diamond 2916 (FIG.25).

In an example, a first electronic device including a processor and amemory in electronic communication with the processor is provided.Stored in the memory are instructions executable by the processor toperform operations.

In an example, an operation may include receiving a bitstream. Anotheroperation may include obtaining a block of level values based on thereceived bitstream. Another operation may include identifying a portionof the level values according to a threshold. Another operation mayinclude, after identifying the portion, processing any remaining ones ofthe level values using a high throughput significance map processingmode. Another operation may include recovering video data based on theprocessing.

In an example, a second electronic device including a processor and amemory in electronic communication with the processor is provided.Stored in the memory are instructions executable by the processor toperform operations. An operation may include transmitting signaling tothe first electronic device, wherein the signaling identifies thethreshold.

According to the above, a significance map may be decodedelement-by-element, e.g. significance map field-by-significance mapfield. When the preset threshold is reached, the electronic device 2422may stop decoding the significance map (the remaining elements of thesignificance map are not decoded). Thereafter, the level values thatcorrespond to the decoded elements are processed using a binarizationmethod (e.g. a binarization method that can send the value zero), whilethe remaining elements are processed using a different binarizationmethod (e.g. a binarization method that cannot send the value zero).Therefore, decoding performance may be improved over conventional CABACsignificance map decoding.

The system and apparatus described above may use dedicated processorsystems, micro controllers, programmable logic devices, microprocessors,or any combination thereof, to perform some or all of the operationsdescribed herein. Some of the operations described above may beimplemented in software and other operations may be implemented inhardware. One or more of the operations, processes, and/or methodsdescribed herein may be performed by an apparatus, a device, and/or asystem substantially similar to those as described herein and withreference to the illustrated figures.

A processing device may execute instructions or “code” stored in memory.The memory may store data as well. The processing device may include,but may not be limited to, an analog processor, a digital processor, amicroprocessor, a multi-core processor, a processor array, a networkprocessor, or the like. The processing device may be part of anintegrated control system or system manager, or may be provided as aportable electronic device configured to interface with a networkedsystem either locally or remotely via wireless transmission.

The processor memory may be integrated together with the processingdevice, for example RAM or FLASH memory disposed within an integratedcircuit microprocessor or the like. In other examples, the memory maycomprise an independent device, such as an external disk drive, astorage array, a portable FLASH key fob, or the like. The memory andprocessing device may be operatively coupled together, or incommunication with each other, for example by an I/O port, a networkconnection, or the like, and the processing device may read a filestored on the memory. Associated memory may be “read only” by design(ROM) by virtue of permission settings, or not. Other examples of memorymay include, but may not be limited to, WORM, EPROM, EEPROM, FLASH, orthe like, which may be implemented in solid state semiconductor devices.Other memories may comprise moving parts, such as a conventionalrotating disk drive. All such memories may be “machine-readable” and maybe readable by a processing device.

Operating instructions or commands may be implemented or embodied intangible forms of stored computer software (also known as “computerprogram” or “code”). Programs, or code, may be stored in a digitalmemory and may be read by the processing device. “Computer-readablestorage medium” (or alternatively, “machine-readable storage medium”)may include all of the foregoing types of memory, as well as newtechnologies of the future, as long as the memory may be capable ofstoring digital information in the nature of a computer program or otherdata, at least temporarily, and as long at the stored information may be“read” by an appropriate processing device. The term “computer-readable”may not be limited to the historical usage of “computer” to imply acomplete mainframe, mini-computer, desktop or even laptop computer.Rather, “computer-readable” may comprise storage medium that may bereadable by a processor, a processing device, or any computing system.Such media may be any available media that may be locally and/orremotely accessible by a computer or a processor, and may includevolatile and non-volatile media, and removable and non-removable media,or any combination thereof.

A program stored in a computer-readable storage medium may comprise acomputer program product. For example, a storage medium may be used as aconvenient means to store or transport a computer program. For the sakeof convenience, the operations may be described as variousinterconnected or coupled functional blocks or diagrams. However, theremay be cases where these functional blocks or diagrams may beequivalently aggregated into a single logic device, program or operationwith unclear boundaries.

One of skill in the art will recognize that the concepts taught hereincan be tailored to a particular application in many other ways. Inparticular, those skilled in the art will recognize that the illustratedexamples are but one of many alternative implementations that willbecome apparent upon reading this disclosure.

Although the specification may refer to “an”, “one”, “another”, or“some” example(s) in several locations, this does not necessarily meanthat each such reference is to the same example(s), or that the featureonly applies to a single example.

1. A system, comprising: a first electronic device of a decoder, thefirst electronic device configured to: receive a bitstream; obtain ablock of level values based on the received bitstream; identify aportion of level values according to a threshold; after identifying theportion, process any remaining ones of the level values using highthroughput a significance map processing mode; and recover video databased on the processing.
 2. The system of claim 1, further comprising: asecond electronic device of an encoder, the second electronic deviceconfigured to: transmit signaling to the first electronic device;wherein the signaling identifies the threshold.